Abstract: An image sensor according to an embodiment includes a first key information storage unit that holds a first secret key SK1 in advance, a communication unit that receives a second public key PK2 corresponding to a second secret key SK2 different from the first secret key SK1 from the external apparatus, a first session key generation unit that generates a session key on the basis of the first secret key SK1 and the second public key PK2, and a first encryption unit that generates, on the basis of a session key generated by the first session key generation unit and image data, coded information including at least one of authenticated information or encrypted information.

Abstract: Communication devices and systems are disclosed. In one example, a communication device is configured to communicate with a communication partner device in accordance with a protocol including a first operation and a second operation. The first operation includes identification information of the communication partner device, write-instructing information, identification information of a first storage unit of the communication partner device, and data to be written in the first storage unit. The second operation follows the first operation and includes identification information of the communication partner device, write-instructing information, identification information of a second storage unit of the communication partner device, information indicating a number of the protocols, and a cyclic redundancy check (CRC) code used to detect an error in the protocol. The second storage unit is configured to store the CRC code and the information indicating the number of the protocols.